2011 Lariat with the 6.7 Powerstroke. Love it and I drive 60+ miles round trip every day for work. I have 36K on mine; but my friend has 110K on his 2011 6.7 and the only time it went into the dealer was for a bad sensor.
I do agree that the big three all have comparable towing capabilities, I just prefer the look of the F-250 over the current GM offerings.